K. A. Kelly et al., in their U.S. Pat. No. 5,738,637, issued Apr. 14, 1998, U.S. Pat. No. 6,234,984, issued May 22, 2001, U.S. Pat. No. 6,325,771, issued Dec. 4, 2001, and U.S. Pat. No. 6,645,163, issued Nov. 11, 2003, as well as their U.S. patent application Ser. No. 9/818,102, filed Mar. 27, 2001, and U.S. patent application Ser. No. 10/705,487, filed Nov. 11, 2003, have provided a remarkable manual device for effectuating CPR on a patient suffering cardiac arrest. The disclosures of these patents and applications are incorporated here by reference. The CPR device of Kelly et al. permits the quick, correct, facile and reliable, manual application of CPR to a person suffering cardiac arrest.
Prior concepts of CPR have focussed on two separate lines of thought. The first of these has instructed individuals to place their hands on the chest of the person in extremis and push down in a repeated cycle. This unassisted CPR suffers from several limitations. Foremost amongst these is the fact that very few individuals, even those supposedly trained in such CPR, can accomplish the task correctly to provide a significant improvement in the patient's chances of surviving the emergency. Further, this type of CPR has only succeeded in placing a force acting downward on the chest of the victim. While this may produce some desired blood flow, it entirely ignores the significant potential of increasing circulation by constricting the person's chest. Not surprisingly, this type of CPR has not proven particularly successful in saving lives of individuals suffering cardiac arrest.
The second type of CPR procedure does the opposite from the first: It circumvents the individual's chest with some sort of sleeve that then undergoes constriction to squeeze the chest and increase the desired blood flow as discussed above. A pneumatic sleeve with an air pressure device often powers this type of apparatus. However, this type of CPR typically fails to a provide downward force into the chest to achieve that assist to the circulation discussed with regards to manual CPR discussed above. Further, this type of apparatus typically requires a substantial financial investment and also necessitates significant training to assure its proper attachment to a patient and subsequent operation, even when “automated.” Notwithstanding the foregoing, significantly improved examples of this type appear in U.S. Pat. No. 4,770,164 issued on Sep. 13, 1988, to R. Lach et al. as well as in the Kelly et al. patents and applications listed above. In fact, the latter show an automated apparatus accomplishing both types of CPR forces, downward and circumferential, discussed above.
Substantial interest has focussed on the ready use of defibrillation on persons suffering from cardiac arrest. While this process has a significant place in the treatment of such persons, it does not aid in bringing oxygen to the heart so that it can function upon defibrillation.
The manual CPR apparatus shown in the Kelly et al. patents and applications facilely accomplish both types of circulation assistance. It allows the downward force placed on it to pass directly into the chest of the patient to effectuate the radial force that directly depresses the chest. However, it also tightens a belt placed around the patient's chest to constrict it and the patient's chest to achieve further and important circulation around the heart muscle.
Significantly, the Kelly et al. device requires a minimal financial investment and virtually no training. This allows its placement in many and varied locations, such as the trunks of police squad cars and at gymnasiums and its use by individuals, such as the police themselves and others like coaches and other institutional personnel. In its simplest form, this CPR apparatus utilizes a belt placed around the victim and attached to a mechanism. When the operator pushes down on the handles forming part of this mechanism, some of the downward force passes straight through to the patient in the form of a radial force directed inward from his or her sternum into the chest. Significantly, the device converts part of the applied downward force into a tangential component that effects a circumferential tightening of the belt around the chest to squeeze it and further promote blood circulation around the heart.
While the Kelly et al. device described in its simplest form above has proven effective for persons with cardiac arrest, the patent and applications listed above disclose many additional features that may enhance its effectiveness in particular situations. Thus, the device may include a backboard to which the belt attaches or through slots in which the belt passes. The backboard may also have a raised portion for the patient's head, and the raised portion may house breathing apparatus and gas (such as oxygen) for the patient.
As other sophistications, the Kelly et al. device may include a force sensor to indicate the pressure applied to the victim's chest. An indicator of this force may then allow the operator to achieve more effective and safe treatment.
As a further safety feature, the apparatus may include a device for limiting the amount of circumferential tightening applied to the patient's chest. In particular, this feature may allow a choice between several different forces applied around the chest.
To assure full chest expansion between down strokes, Kelly et al.'s device may incorporate a component on its chest-contacting surface for adhering the device to the chest. Upon the release of pressure, this adherence will assist to expand the chest by pulling up on the patient's torso. This adhering device may take the form of suction cups or even some form of adhesive.
Kelly et al. also suggest a signal generator forming part of their device. This component has the purpose of producing a periodic signal. This signal simply informs the operator when to push down on the apparatus and helps achieve a rhythmic application of force at the interval that portends the greatest positive effect on the patient.
The apparatus may also include two or more electrodes, spaced apart from each other, that contact the patient's chest at different locations for the purposes discussed below. Two electrodes may attach to the base of the device which sits on the chest. Alternately, one may attach to the base while a second connects to the belt. Or, the two may attach at different locations along the longitudinal axis of the device's belt. Or, with more, the electrodes may attach to the belt and at several locations around the belt.
The electrodes may serve to obtain an electrocardiogram of the patient. Alternately or additionally, the electrode may defibrillate the heart when necessary.
As seen from the above, the Kelly et al. device has provided vastly improve CPR to individuals in dire need of such treatment. Naturally, the work continues to improve this mechanism even further.